The present invention relates to a dispensing device or a liquid applicator having a compressive means for compressing a liquid chamber containing a predetermined liquid, such as cosmetic appliances including eye-liners and nail polishers, etc. and writing instruments such as ball point pens and correction devices employing a correction liquid.
An example of the prior art liquid applicators which is shown in Japanese Pre-grant Patent Publication No. 10-28921 will be explained. In this publication, a main body containing a liquid material has, at its rear portion, a cylinder chamber which has a piston slidably. At a forward portion of the cylinder chamber, a check valve which is rearward-biased by a spring force of a coil spring is provided so that a forward portion of the check-valve constitutes a liquid container portion.
At the front end of the main body, an applicator tip is disposed and a valve body which is spring-biased in a forward direction is disposed at an applicator opening of the applicator tip.
When the piston is advanced, the cylinder chamber is compressed to release the check valve by the compression force, and the compressed air is fed into the liquid container portion, so that the liquid in the liquid container portion is compressed. In the compressed state described above, the valve body is retracted to thereby discharge the liquid.
In the prior art described above, there is an advantage that liquid application (that is, discharging of a liquid) can successfully be made even when the applicator is positioned with its application tip is positioned upward or directed upward, because the liquid is compressed. As the liquid is decreased by use, however, new air is introduced into the device, and there are cases that that the liquid is dried and, in the worse case, it is completely solidified. Further, unwanted bacteria in the air get mixed with the liquid to result in a deterioration or a change in quality of the liquid and this is unfavorable particularly when the liquid is used for cosmetics.
In view of the above, it is an object of the present invention to provide a new applicator which are free from the disadvantages that are inherent to the conventional technique described above.
In a first aspect of the present invention, there is provided an applicator comprising a tubular main shaft body containing therein a liquid, a compressive means, disposed at a rear portion of the tubular main shaft body, for compressing the liquid, a non-return device positioned at a rear portion of the liquid and movable along with a decrease of the liquid, and a valve mechanism between the non-return device and the compressive means.
In the structure described above, the non-return device can be made of a liquid material and a solid material.
Further, in the present invention, the non-return device has a large-diameter portion and a small-diameter portion.
Further, a refill is provided in the tubular main shaft body, and the refill has a liquid container tube, a tip holder press-fitted to a front portion of the liquid container tube, and a ball press-fitted to a front portion of the tip holder. Two kinds of greases are disposed at the rear end of the liquid to prevent the liquid from flowing out from a rear end of the liquid container tube. The greases can contain therein a float made of a synthetic resin.
The two kinds of greases include an aqueous (or water-soluble) grease and an oil grease.
The float can have a small-diameter portion at its front portion and a large-diameter portion at the rear portion such that small-diameter portion has a larger diameter than a minimum inner diameter of the tip holder.
In a further (second) aspect of the present invention, there is provided an applicator comprising a tubular main shaft body containing therein a liquid, a compressive means, disposed at a rear portion of the tubular main shaft body, for compressing the liquid, a non-return device positioned at a rear portion of the liquid and movable along with a decrease of the liquid, and a valve mechanism between the non-return device and the compressive means, wherein the valve mechanism is retractable and returnable to its original position so that when the valve mechanism is retracted (that is, moved backward), the compressive force is decreased or released.
In the second aspect of the invention, the valve mechanism can be formed of a rubber-like resilient material.
In a further (third) aspect of the present invention, there is provided an applicator comprising a tubular main shaft body containing therein a liquid, a compressive means, disposed at a rear portion of the tubular main shaft body, for compressing the liquid, a non-return device positioned at a rear portion of the liquid and movable along with a decrease of the liquid, and a valve mechanism at a rear portion of the non-return device so that the liquid is compressed by means of the valve mechanism.
In the third aspect of the invention, a front air space is formed at a front portion of the valve mechanism and a rear air space is formed at a rear portion of the valve mechanism, and the front air space is communicated with the rear air space by a small through-hole.
In a further (fourth) aspect of the present invention, there is provided an applicator comprising a tubular main shaft body containing therein a liquid, a compressive means, disposed at a rear portion of the tubular main shaft body, for compressing the liquid, a non-return device positioned at a rear portion of the liquid and movable along with a decrease of the liquid, and a valve mechanism between the non-return device and the compressive means, wherein the valve mechanism has a first valve device for opening/closing in the direction of the liquid and a second valve device for opening/closing in the direction of the compressive means, wherein the second valve device has a stronger closing force than the first valve device.
According to the present invention, air which is introduced from the outside is compressed by the compressive means and then the compressed air serves to compress the liquid through the non-return device.